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    <meta charset="UTF-8">
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    <title>Document</title>
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<body>
    <script>
        // const person = {
        //     name: "jack",
        //     age: 21,
        //     language: ['java','js','css']
        // }
        // console.log(Object.keys(person));
        // console.log(Object.values(person));
        // console.log(Object.entries(person));

        // const as = 12 ;
        // const asd = 45;
        // const person2 = {as, asd}
        // console.log(person2)

        // const p1 = {name: "javk",age:"12"}
        // const p2 = {...p1};
        // console.log(person2)
        let arr = ['1','20','-5','3']
        arr = arr.map(item=>item*2);
        console.log(arr)

        arr.reduce((a,b,c,d)=>{
            console.log("上一次处理后：" + a)
            console.log("当前正在处理：" + b)
            console.log("c = " + c)
            console.log("d = " + d)
            return a+b
        },100)

    </script>
</body>
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